1. Field of the Invention
The present invention relates to a capacitor block used for a filter circuit and, in particular, to a capacitor block including a plurality of capacitors electrically connected to each other and a laminated board having the capacitor block.
2. Description of the Related Technology
This type of capacitor block is described in, for example, Japanese Patent No. 2978553. The capacitor block includes a laminated board incorporating a plurality of capacitor electrodes. Two of the capacitor electrodes disposed in the outermost layers function as GND electrodes. Two or more capacitor electrodes sandwiched by the two outermost layers are laminated with a dielectric layer therebetween. Since a ground-type π or T capacitor block having such a structure requires no conductors that connect the capacitors to each other and the GND electrodes are disposed in the outermost layers, the stray capacitance can be advantageously reduced.
However, in this capacitor block, capacitor electrodes to be connected to external terminals are disposed close to each other. Accordingly, when the size of the capacitor block is reduced and the distance between the capacitor electrodes is decreased, extra parasitic capacitance is generated. As a result, it becomes difficult to design a variety of filters. Conversely, if the distance between the capacitor electrode is increased in order to reduce the parasitic capacitance, the size of the capacitor block is increased, and therefore, realizing a compact capacitor block is difficult. In addition, since the capacitor block has a sandwich structure with the two outermost GND electrodes, it is difficult to form a compact filter circuit having more than three stages that require more than two GND connections.